Technical Field
The invention relates to a network communication technique. Particularly, the invention relates to a network structure based on a digital subscriber loop (xDSL) and a public switched telephone network (PSTN) and central office equipment (COE) and customer premises equipment (CPE) thereof.
Related Art
If data transmission, transmission of telephone voice and reverse power supply are simultaneously performed between central office equipment (COE) and customer premises equipment (CPE) of a digital subscriber loop (xDSL), two twisted-pair cables have to be established, where one of the twisted-pair cables is in charge of the data transmission and the transmission of telephone voice, and another one of the twisted-pair cables is in charge of independently supplying power (for example, supplying power from the CPE to the COE).
Alternatively, one twisted-pair cable is in charge of data transmission and reverse power supply, and the other twisted-pair cable is in charge of transmitting telephone voice.
Since the COE provides a forward power for transmitting telephone voice, when the reverse power supply is supplied, power supply confliction is generated, and transmission of telephone voice and the reverse power supply cannot coexist on the same twisted-pair cable. Therefore, when the related equipment is established, a twisted-pair cable has to be additionally added to avoid coexistence of the transmission of telephone voice and the reverse power supply on the same twisted-pair cable, so as to achieve an effect of simultaneously implementing data transmission, transmission of telephone voice and reverse power supply. Since the existing solution is to additionally add one twisted-pair cable, besides that the existing network lines have to be adjusted, implementation cost is also increased. Due to aging of the twisted-pair cables, a whole maintenance cost is increased.